While this hasnthasn't been explained exactly point for point i, I do believe the answer is revealed in one of the more recent chapters. SPOILERS!!!!!!!!!!!!!!!!!!! SPOILERS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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Igneel is somehow inside of Natsu and Igneel is well older than the required age to hold him back same with gajeel.
Igneel is somehow inside of Natsu, and Igneel is well older than the required age to hold him back. Same with Gajeel.